The present invention relates to a quick connector to be adapted for assembly in a fuel piping, for example, a fuel piping of an automobile, and more specifically, to sealing means to provide a seal between a pipe and a connector housing.
In a gasoline fuel piping structure, for example, a gasoline fuel piping structure of an automobile, a quick connector (A) as shown in FIG. 11 is used for joining a tube to a pipe. The quick connector (A) has a tubular connector housing (B) and a retainer (C) fitted in the tubular connector housing (B). The tubular connector housing (B) is provided with a tube connecting portion (D) on one axial end thereof and a pipe inserting portion (E) on an opposite axial end thereof, and the pipe inserting portion (E) has an projection receiving portion (F) on an opposite axial end thereof wherein the retainer (C) is fitted. A pipe is relatively inserted into an insertion opening on an end of the tubular connector housing (B), the pipe inserting portion (E) or the projection receiving portion (F) so as to snap-fit in the quick connector (A), and thereby the quick connector (A) is connected to the pipe. As shown in FIG. 12, a pipe (G) to be connected to the quick connector (A) is formed with an inserting end portion (H) on one axial end thereof, and the inserting end portion (H) of the pipe (G) is provided with an annular engagement projection (I) on an outer peripheral surface thereof. The inserting end portion (H) of the pipe (G) is inserted in the pipe inserting portion (E) of the tubular connector housing (B), the annular engagement projection (I) snap-engages with the retainer (C), and thereby the pipe (G) snap-fits in the quick connector (A).
The pipe inserting portion (E) has a seal holding portion (J) which is formed smaller in diameter than the projection receiving portion (F) on one axial end of the projection receiving portion (F). Sealing means (K) is disposed in the seal holding portion (J) on one axial end thereof to provide a seal between the pipe inserting portion (E) and the inserting end portion (H) of the pipe (G). The sealing means (K) comprises annular sealing member (L) made of elastic material, which prevents gasoline from leaking out between the tubular connector housing (B) and the pipe (G).
Meanwhile, an annular sealing member (L) adapted to the sealing means (K) is preferably made of elastic materials of gasoline resistant property to deal with environmental problems by reducing the amount of gasoline fuel permeation from the quick connector (A), or to prevent the annular sealing member (L) from swelling due to contact with gasoline and thereby losing elasticity. On the other hand, for the sealing means (K), low-temperature resistant properties are required in order to prevent the sealing property of the sealing means (K) from decreasing in cold temperature, for example, in an automobile used in cold climate regions, and thereby gasoline from leaking out. Then, a technical construction is employed wherein the sealing means (K) is constructed by two annular sealing members (L), (L) disposed axially in side by side relation as shown specifically in FIGS. 11 and 12. The annular sealing member (L) of one axial end, which is in contact directly with gasoline, is a material having gasoline resistant property, and the annular sealing member (L) of an opposite axial end is a material having low-temperature resistant property, so that the sealing means (K) is provided with both high gasoline resistant property and low-temperature resistant property.
However, in case that the quick connector (A) is disposed upright or in a direction longitudinally thereof, with an insertion opening upward and the tube connecting portion (D) downward, or in case that a large engagement window (M) to be engaged with the retainer (C) is provided on the projection receiving portion (F) of the connector housing (B) as specifically shown in FIGS. 11 and 12, a relatively large amount of water and dust are likely to migrate between the connector housing (B) and the pipe (G). If the water remains in contact with the pipe (G) between the connector housing (B) and the pipe (G), it eventually causes corrosion on the pipe (G) connected with the quick connector (A). And, if a relatively large amount of water and dust migrate between the connector housing (B) and the pipe (G), there is also a fear that a considerable amount of water and dust penetrate along up to the annular sealing member (L) of an opposite axial end. In a state where a considerable amount of water and dust have penetrated up to the annular sealing member (L) of an opposite axial end, if vibration is exerted on the quick connector (A) or the inserting end portion (H) of the pipe (G), and thereby slight relative sliding movement and/or slight relative rotational movement occur repeatedly between the connector housing (B) and the pipe (G), for example, due to gasoline fuel piping connected to vibration source such as a gasoline engine, the annular sealing member (L) of an opposite axial end is eventually worn off and deteriorated. In case that the annular sealing member (L) of an opposite axial end is deteriorated, if elasticity of the annular sealing member (L) of one axial end is lowered, for example, in cold climate regions, the sealing means (K) eventually loses sufficient sealing function against gasoline fuel.